cheap, easy to make, durable prototyping material?

Question

I'm interested in making largish models (prototypes) on a tight (student) budget. If it is possible (there are always trade offs...) the material should be stronger (stiffer) than weaker (consider cardboard as the low end), and I want to be able to mark it, spray paint it, etc. Don't mind having to make it; but it shouldn't take too long to make (a week is entirely too long; remember, it's all about the prototyping!). In that vein, volume resolution doesn't need to be great. Any ideas? (if no one has ideas, I'll ask the engineering category)

Answer 1

It depends a bit on what you need to be able to do with the prototypes. If they need to be put under stress (like a gear or a carrier frame) you probably have to go for woods and metal.
If not then high density foam is proably easiest and fastest to work with. It also allows for carving complex shapes. If it's to be put under stress then you may need to back it up with wood. You may also have to come up with somethig to seal the surface if you need it smooth (high gloss spray paint? Acrylic floor wax?).
If it comes to sheet materials I'd suggest high density cardboard, plastic card and foam board.
Plaster of paris is cheap and you can use a combination of metal mesh and plastered bandages to crate large shapes. This could be a bit brittle though.

Answer 2

I agree with the previous poster. It all depends on the shape, size, and amount of detail you need to create, and also what you need it to be able to do later re strength, waterproofness, etc.

There are loads of materials that can be "modeled" with, inclusing sheets or rods or "strings" of metal, PVC and other plastics, wood, wire and mesh, papier mache of various types, all kinds of clays (over armatures or solid or hollow)etc., etc. And there are various ways to make even weak ones fairly strong engineering-wise. (So you might want to add more info about exactly what you're wanting to make, etc., to get better answers.)

P.S. If you're interested in the polystyrene foam the previous poster mentioned, the type you'll find in hardware stores in sheets intended for various insulation purposes is strong and big and waterproof, and it can be cut and shaped a lot (with serrated knives, sandpaper and rasps, hot wires or hot tools, etc.); it can also be glued together in stacks, then sculpted with those tools to make much thicker rounder objects.
Check out this site at least for more info on some of those things:
http://hotwirefoamfactory.com


HTH,

Diane B.